=begin
I'm not sure what category this one goes to so I apologise if I picked the wrong one.

I believe the syntax highlighting in the ruby-mode for emacs in /misc/ruby-mode.rl is broken for certain regular expressions. The RE will then be interpreted as non-RE Ruby code and the string quote counting gets all confused, too. Just fire up the test file I attached in emacs with ruby-mode and it should be fairly obvious.